to test the hypothesis that activity restriction in women with singleton gestations and with arrested PTL would reduce the rate of PTB.

Preterm birth (PTB) is a major cause of perinatal morbidity and mortality. Worldwide, about 15 million babies are born too soon every year, causing 1.1 million deaths, as well as short- and long-term disability in countless survivors.

Preterm labor (PTL) is the final pathway for about 50% of all PTB. Tocolytic agents are drugs that can slow or stop labor contractions in the attempt to delay births preceded by PTL. Primary tocolysis is defined as tocolysis given on initial presentation of women with PTL. In most of these women, PTL stops, but as their risk of PTB remains high, some have advocated use of maintenance tocolysis, i.e. tocolysis after arrested PTL. So far, no maintenance tocolytic agent has been shown to be beneficial in preventing PTB.

Some authors have also advocated the use of activity restriction in women with arrested PTL to reduce the risk of PTB. Activity restriction is defined as the following forms of activity restriction: pelvic rest and prohibition of sexual activity, reduction of work and/or non work activity. So far, the benefit of activity restriction in women with arrested PTL is still subject of debate and no Randomized Controlled Trial (RCT) has been undertaken.

Thus, the aim of this trial is to test the hypothesis that activity restriction in women with singleton gestations and with arrested PTL would reduce the rate of PTB.

Inclusion Criteria:

• singleton gestations;
• arrested PTL;
• TVU CL < 25 mm;
• 18 years to 50 years.

Exclusion Criteria:

• multiple gestations;
• symptoms of PTL (not arrested PTL);
• TVU CL ≥ 25mm;
• premature rupture of amnion and chorion membranes (PROM) at the time of randomization;
• cerclage in situ at the time of randomization;
• pessary in situ at the time of randomization;
• vaginal bleeding at the time of randomization;
• women who are unconscious, severly ill, mentally handicapped;
• women under the age of 18 years or over the age of 50 years.

only pregnant women (limit to Female)